Facile SERS-active chip (PS@Ag/SiO2/Ag) for the determination of HCC biomarker

Manipulation and Applications of Hotspots in Nanostructured Surfaces and Thin Films

“…With increasing deposition time, the surface roughness of the SiO 2 −Ag nanocaps increases, and the nanogaps between the units of bridged knobby units gradually decrease ( Figure 4 b–d). The results of FDTD simulations indicate that the hotspots where the EM field is coupling are mostly distributed on the surface of the SiO 2 -isolated Ag nanoparticles on the nanocaps and the bridges between nanocaps, as shown in Figure 4 e. In addition, the trilayer or multilayer Ag/SiO 2 composite shell or 3D pillar-cap arrays also significantly improve the enhancement of the EM field, which manipulates the distribution of hotspots [ 29 , 45 , 51 ]. The SiO 2 addition not only immensely increases the surface roughness of the designed nanostructure surfaces and thin films but also improves the enhancement of the EM field at the nanogaps, which manipulates the formation and evolution of hotspots.…”

“…Furthermore, three-axis symmetric nanostructured arrays are obtained using linearly polarized oblique waves with a incidence angle of 50 degrees. The manipulation of hotspots can be used to accurately control a chemical reaction at the nanometer level, which has significant applications [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 53 , 55 ].…”

“…Various nanostructured surfaces and thin films can be achieved by the combination of NSL and physical vapor deposition, such as periodic nanocaps [ 14 , 15 , 16 , 17 , 18 ], nanotriangles [ 19 , 20 , 21 , 22 ], nanobowls [ 23 , 24 , 25 ], nanorings [ 26 , 27 , 28 ], nanopillars [ 29 , 30 ], nanocones [ 31 , 32 , 33 ], and other complex nanostructured surfaces and thin films, including nanohoneycomb, bridged knobby units, nanoparticle cluster-in-bowl arrays, and so on [ 2 , 25 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. These architectural designs of nanostructured surfaces and thin films can be obtained by controlling a series of deposition processes (the deposition time, angle, distance, and so on), PS colloid sphere etching, transfer, and their combination steps, which manipulate the formation, distribution, and evolution of hotspots and have significant implications in broad applications [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 …”

SERS Immunosensor of Array Units Surrounded by Particles: A Platform for Auxiliary Diagnosis of Hepatocellular Carcinoma

“…Figure 3 b also visually displays the changes of peak intensities at 1436 cm −1 and 1375 cm −1 . The SERS characteristic peak intensity increased when the etching time of the PS templates increased from 10 to 30 s. The gap between the AgNPs enhanced the plasmon coupling effect and made the vibration wavelength of the surface plasmon better match the excitation wavelength to generate LSPR, caused more electric fields to be generated around this area, and generated numerous hot spots, which enhanced the SERS activity [ 33 , 41 ]. Therefore, as the etching time increased and the distance between the spheres increased, the plasmon coupling of adjacent AgNPs on the array of units surrounded by particles was enhanced and led to the increase in SERS intensity.…”

Controlling the 3D Electromagnetic Coupling in Co-Sputtered Ag–SiO2 Nanomace Arrays by Lateral Sizes

“…Silica-based nanocomposites have been widely studied due to some important properties. As an ideal support for nanomaterials, silica is generally thermally stable, water-soluble, nontoxic, biocompatible, and has high colloidal stability [ 26 , 27 ]. Composite metal nanostructures can be used as a SERS platform to provide great electromagnetic field enhancement, because the superior properties of composite nanostructures are allocated to single component [ 28 , 29 ].…”